Some Nonlinear Electromechanical Properties of Thin PZT and ZnO Compositions Deposited on the Si-Substrate

Abstract

The paper deals with electromechanical properties of piezoelectric PZT (54/46) compositions near MPB, (001)-orientation, rhombohedral PZT (60/40) (111), and ZnO (002) thin films sputtered on the Pt/Ti/SiO₂/Si substrates. The thin film samples were investigated under high electric excitations and corresponding strains. The samples exhibit frequency dispersion and nonlinear piezoelectric response (hysteresis), i.e. the nonlinear dependence of the mechanical displacement d ₀ (or effective piezoelectric coefficient d _33,eff ) on the electric field. I the case of ZnO samples, the remarkable decrease of the mechanical displacement d ₀ in the frequency range (0.1–1.5) kHz was found. These results are compared with data obtained on the PZT (60/40) (111) sample. The nonlinear electromechanical properties of the PZT and ZnO thin films were investigated using the original double beam laser interferometer at room temperature. The results are discussed and compared with the published data.

Keywords:

• PZT and ZnO thin films
• rf sputtering
• piezoelectric constants
• Si substrate
• electromechanical non-linear properties

PACS:

• 77.80.−e
• 73.61.Ga
• 77.65.−j

Acknowledgment

This research was supported by Czech Science Fondation, Project No.202/07/1289. Authors thank Pavel Mokrý for reading the manuscript.